The invention is in the field of mechanical engineering and fine mechanics and can in particular advantageously be used in the medical area.
In this respect, the subject matter is a pump arrangement in accordance with the preamble of claim 1.
Pump arrangements are increasingly known from prior art in particular for use in the body's own vessels. Said pumps can be used, for example, for short-term cardiac support to relieve the cardiac muscle of a patient after a cardiogenic shock (myocardial infaction). In this process, use is sometimes made of transfemorally implanted micro-axial pumps.
Such a pump arrangement is known, for example, from EP 2 047 872 A1. The pump arrangement disclosed there includes a pump, a sheath receiving the pump and having a distal intake opening and a proximal outflow opening, with the pump generating a driving flow in operation from the distal intake opening toward the proximal outflow opening. A flow passage thus extends between the intake opening and the outflow opening. The pump is in this respect arranged in a first fluid-tight section of the sheath which has the distal intake opening and which is formed as a PU covering of a housing. Furthermore, a second fluid-tight section of the sheath is present which includes the proximal outflow opening and is formed as an outflow hose. The outflow hose is connected with material continuity to the PU covering. The pump arrangement is arranged such that the pump formed as a rotor can, for example, be arranged in a ventricle, with the outflow hose extending from the ventricle into the aorta.
All the blood entering into the aorta via outflow openings of the outflow hose moves through the intake opening into the flow passage formed by the sheath and in so doing passes through the rotor. In other words: The conveyed flow conveyed by the pump is identical to the total flow exiting at the outflow opening.
The subject matters of documents DE 41 24 299 A1, DE 10 2004 054 714 A1, WO 2007/112033 A2 and US 2008/132748 A1 also work in accordance with the aforesaid principle.
Since all blood comes into direct contact with the pump, a particularly high effort is required in the manufacture of the pump to reduce the blood-damaging effect of the moving pump parts. This blood-damaging effect is manifested in direct mechanical shear at moving and stationary pump parts and in shear by shear stress fields occurring in the fluid while passing through the flow passage (see above). Pump geometries therefore also arise which cannot be used by means of a minimally invasive procedure.